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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Characterisation of the MIRI spectrometer, an instrument for the James Webb Space Telescope

Briggs, Michael January 2010 (has links)
The MIRI-MRS is a future space based Medium Resolution Spectrometer and one of four instruments to be integrated onto The James Webb Space Telescope. The Medium Resolution Spectrometer is designed to be diffraction limited across its entire passband of 5 - 28.3 microns. It achieves this through the spectral filtering of the passband into four channels with each one containing an integral field unit optimised for minimal diffraction losses. The integral field unit enables the simultaneous measurement of the spectral data across the entire field of view. The design of the Medium Resolution Spectrometer is outlined with particular reference to the choice of slice widths used for each channel to minimise the diffraction losses from the slicing mechanism. The slice widths are also used to derive the extent of the field of view and combined with the along slice plate scale at the detector the technique required for complete spatial sampling of the spectrometer is outlined. The operation of the Channel 1 image slicer component was tested cryogenically at 5 microns for diffraction losses due to the slicing of the point spread function. This was so that the actual diffraction losses could be measured and compared with the optical model. From the resulting analysis I concluded that the operation of the image slicers were well understood for diffraction losses. Performance tests were required on the instrument because of its novel design. This was the first implementation of an integral field unit operating between 5 - 28.3 microns and it was necessary to ensure that the operation of the image slicer did not induce unacceptable diffraction losses into the instrument. Tests were required on the assembled instrument to verify the optical design. A Verification Model of MIRI was built to enable test verification of the optical design. This testing was carried out in advance of the MIRI Flight Model assembly so that changes could be made to the Flight Model design if necessary. This testing phase was also designed to define the calibration process necessary to prepare the MIRI Flight Model for scientific operations. For the testing phase it was necessary to create an astronomical source simulator. This MIRI Telescope Simulator was constructed in Madrid where I spent two months ensuring the point source movement across the field of view would be sufficient to investigate the Medium Resolution Spectrometer. My contribution was to help assemble both the Verification and Flight Models. I also participated in the Verification Model testing phase from the test design phase to the test implementation and data analysis. My role in the analysis was to investigate the field of view of the Medium Resolution Spectrometer Verification Model and whether the field of view requirements for the spectrometer were met. During this analysis I also verified that the diffraction effects of the end-to-end instrument were well understood by the optical model. The Medium Resolution Spectrometer Verification Model field of view compromised the field of view requirement for the spectrometer. A similar analysis for the Flight Model showed that there would be a low probability that the field of view requirement would be met. As a result of the analysis I defined a new slit mask design that would align the field of view sampled by Channel 1 to increase the aligned field of view. As a result there is a high probability that the field of view requirement for the Flight Model will be exceeded. The test analysis discovered a magnification effect within the spectrometer which must be properly characterised to enable accurate field of view reconstruction. I designed a test necessary for the calibration phase of the Flight Model to enable full spatial alignment of the Medium Resolution Spectrometer. I also measured an excess flux level in the Channel 1 observations at the detector and there was a ghost detected in the Channel 1 images. Whilst the origin of either the excess flux or the ghost could not be completely determined I investigated the possibility that they will not be present in the Flight Model due to the slight design differences. If present however they will not increase the background level of an observation above the requirement outlined for Channel 1.
212

Short-scar facelift without temporal flap: a 10-year experience.

Centurión, Patricio, Romero, Carolina, Olivencia, Claudia, Garcia, Ronald Gamarra, Pardo, Paul Kaufmann 08 1900 (has links)
BACKGROUND: The understanding of facial anatomy and its changes through aging has led to the development of several different facelift techniques that focus on being less invasive and traumatic and, at the same time, providing natural long-lasting results. In this article we describe step by step our facelift technique as it has been done over the past 10 years by the senior author. METHODS: This is a retrospective, descriptive, transversal study in which all patients who underwent a rhytidectomy using our technique from January 2002 to September 2012 were included. All patients were operated on under local anesthesia and superficial conscious sedation. All surgeries were performed by the same surgeon. A complete step-by-step description of the surgical technique can be found in the main article. RESULTS: Between January 2002 and September 2012, a total of 113 patients underwent facelift surgery. Of these, 88.9 % were women and 11.1 % were men. The mean age was 55.3 (± 8.66) years. Primary surgeries represented 80.3 % (n = 94), secondary 18.8 % (n = 22), and tertiary 0.85 % (n = 1). Only one major complication, representing 0.8 %, consisting of a right-sided temporal paresis with 2 months complete recovery was seen. The minor complications rate was 23.1 %. The most common minor complication was hypertrophic/keloid scars which made up 77.8 % of all minor complications. CONCLUSIONS: The technique described provides good and long-lasting aesthetic results with shorter scars, smaller areas of dissection (without temporal and postauricular flaps), and a shorter recovery period. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .
213

A Behavioral-Technological Approach to Increasing Attention-to-Task Behavior in "Hyperactive" Children

Stevens, Larry Charles 05 1900 (has links)
The present study sought to alleviate the response cost inefficiency of the behavioral approach to controlling classroom hyperactivity by increasing the observer-student ratio via behavioral-electronic technology. A portable, integrated-circuit, counting and timing device was developed to enable immediate time-sequenced data recording and reinforcing of eight target behaviors by a single observer. A multiple-baseline design, across matched individuals was utilized to demonstrate the reinforcing effects. The results indicated a significant increase over mean baseline frequency in attention-to-task behavior for the group of eight students. It was concluded that by utilizing the behavioral-technological intervention strategy applied in this study, one observer could accurately monitor and reinforce eight students simultaneously and subsequently increase task attentiveness.
214

Vyhodnocení aktivity potenciálně antimykotických látek pomocí mikrodiluční bujónové metody III / Evaluation of activity of potentional antimycotic substances through the use of microdilution broth method III

Zavřelová, Alena January 2015 (has links)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Title of thesis: Evalution of activity of potentional antimycotic substances through the use of microdilution broth method III Autor of thesis: Alena Zavřelová Supervisor: Mgr. Klára Konečná, Ph.D. Background: The aim of this thesis, due to the growing incidence of fungal diseases and the growing incidence of resistance, was to determine the activity of potentially antimycotic active substances. We tested newly synthesized compoused, structurally based on the substance of pyrazinamide which is significant antituberculotic. Methods: Testing of substances was carried out using a broth microdilution method on eight strains of pathogenic fungi consisting of five yeast strains: Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata, Trichosporon asahii and three strains of filamentous fungi: Aspergillus fumigatus, Absidia corymbifera, Trichophyton mentagrophytes. Results: From the range of tested concentrations and from the total number of the thirty tested substances, the most noticeable antifungal aktivity was revealed in the substance of 5-methyl-6-(2-phenylhydrazinyl)pyrazine-2,3- dicarbonitrile. All strains, except Trichophyton mentagrophytes strain, showed a relatively...
215

Vyhodnocení aktivity potenciálně antibiotických látek pomocí mikrodiluční bujónové metody II / Evaluation of activity of potentional antibiotic substances through the use of microdilution broth method II

Kopečná, Klára January 2016 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of biological and medical sciences Study program: Pharmacy Autor: Klára Kopečná Supervisor: Mgr. Klára Konečná, Ph.D. Title of diploma thesis: Evaluation of activity of potencional antibiotic substances through the use of microdilution broth method II Background: To evaluate the antibacterial activity of the compounds synthesized by the Department of Pharmaceutical Chemistry and Drug control, Faculty of Pharmacy in Hradec Králové, Charles University in Prague under the leadership of prof. PharmDr. Martin Doležal, Ph.D. Methods: Using broth microdilution method was tested antibacterial activity at eight bacterial strains, namely Staphylococcus aureus, Staphylococcus aureus methicilin resistant, Staphylococcus epidermidis, Enterococcus sp., Escherichia coli, Klebsiella pneumoniae, Klebsiella pneumoniae ESBL positive and Pseudomonas aeruginosa. Results: Test substances were divided into 5 groups according to similarities in the chemical structure. The best antibacterial activity was observed in the group of derivatives of N-benzyl- 6-(alkylamino)pyrazine-2-carboxamide. Conclusion: Antibacterial activity was detected in 10 of 24 tested compounds. From active substances, all but one danced only Gram-positive bacteria. Among...
216

Trh práce a nezaměstnanost / Labor market and unemployment

Rylichová, Zuzana January 2013 (has links)
In recent years became unemployment one of the most important economical issues. Increasing rate of unemployment is one of the most serious problems of most states. The goal of all of them is to ensure the maximal balance between supply and demand on the labour market. The purpose of the master thesis is to describe the basic aspects of labour market and unemployment, but primarily to describe the special instruments of the Austrian labour market and find some recommendations, which could be helpful and could be implemented to the system in the Czech Republic. First three chapters deals with the theoretical basis of the topic and terminology. First chapter describe the functioning of the labour market and specific attributes of the supply and demand on the labour market. Chapter two, which deal with the unemployment, define the origin of unemployment, kinds of unemployment and consequences of unemployment to the society. The third chapter concern to the topic of minimal wages and compare the advantages and disadvantages of the statutory minimal wages. Chapter four summarise the development and instruments of the employment policy of the European Union, because this policy has influence on the system in the Czech Republic and also in Austria. The last and the most important chapter of the thesis...
217

Moduly s minimální množinou generátorů / Moduly s minimální množinou generátorů

Hrbek, Michal January 2013 (has links)
Title: Modules with a minimal generating set Author: Michal Hrbek Department: Department of Algebra Supervisor: Mgr. Pavel Růžička, Ph.D., Department of Algebra Abstract: By a minimal generating set of a module we mean a subset which generates the module but any of its proper subsets does not. If the module is not finitely generated, an existence of a minimal generating set is not guaranteed. We say that a module is weakly based if it has a minimal generating set. In the presented thesis, we provide a characterization of weakly based modules over Dedekind domains. As an application of this, we show that the class of weakly based modules is not closed under extensions and the complement of this class is not closed under finite direct sums. Also, we show an example of an abelian group which is weakly based if and only if CH holds. Then we treat rings such that all modules are weakly based. We prove that a Baer regular ring has this property if and only if it is semisimple, and we show that any ℵ0-noetherian commutative semiartinian ring has this property. Final part of the text concerns the problem of Nashier and Nichols - does any generating set of any module over a perfect ring contain a minimal generating set? Keywords: module, minimal generating set, weak basis 1
218

Algoritmický přístup k resolventám v teorii reprezentací / An algorithmic approach to resolutions in representation theory

Ivánek, Adam January 2016 (has links)
In this thesis we describe an algorithm and implement a construction of a projective resolution and minimal projective resolution in the representation the- ory of finite-dimensional algebras. In this thesis finite-dimensional algebras are KQ /I where KQ is a path algebra and I is an admissible ideal. To implement the algorithm we use the package QPA [9] for GAP [2]. We use the theory of Gröbners basis of KQ-modules and the theory described in article Minimal Pro- jective Resolutions written by Green, Solberg a Zacharia [5]. First step is find a direct sum such that i∈Tn fn∗ i KQ = i∈Tn−1 fn−1 i KQ ∩ i∈Tn−2 fn−2 i I. Next important step to construct the minimal projective resolution is separate nontri- vial K-linear combinations in i∈Tn−1 fn−1 i I + i∈Tn fn i J from fn∗ i . The Modules of the minimal projective elements are i∈Tn (fn i KQ)/(fn i I). 1
219

Kortikale ryping, omgewingstimulasie en hiperaktiwiteit by kinders met 'n aandaggebreksteurnis

16 February 2015 (has links)
M.A. (Psychology) / Please refer to full text to view abstract
220

Aditivos na redução de oxidação enzimática em beterraba minimamente processada / Additives in the reduction of enzymatic oxidation in minimally processed red beet

Vieira, Allan Patrick de Abreu 15 March 2019 (has links)
O esbranquiçamento é o principal problema pós-colheita em beterraba minimamente processada. Esse problema consiste no ressecamento das células superficiais do produto, resultando no aspecto esbranquiçado decorrente do bloqueio das células túrgidas e íntegras das camadas inferiores. As etapas de corte e a manipulação durante o preparo dos produtos minimamente processados (PMPs) podem ser consideradas fonte de estresse abiótico, que estimula a formação de espécies reativas de oxigênio (EROs). O acúmulo de EROs provoca alterações bioquímicas e estruturais nas células, ocasionando alterações visuais e nutricionais que afetam diretamente a qualidade comercial. Aditivos alimentares são utilizados para retardar a degradação dos PMPs, mantendo-os frescos e adequados para o consumo por mais tempo. Ácidos orgânicos e aminoácidos são aditivos do tipo GRAS (Generally recognized as safe), ou seja, seguros para alimentos e são amplamente utilizados em produtos hortícolas. O objetivo deste trabalho foi avaliar a eficácia da arginina no controle do esbranquiçamento em beterraba minimamente processada e comparar com os demais aditivos utilizados comercialmente. Desse modo inicialmente foi determinada a combinação mais eficaz de dose e pH de aplicação da arginina, com avaliação de quatro doses (0, 10, 25 e 50 mM) combinadas com três faixas de pH (inalterado, pH 6,0 e pH 7,0). A aplicação de arginina apresenta resultados promissores em relação ao retardo do esbranquiçamento em beterraba minimamente processada, principalmente para o tratamento com 25 mM de arginina em pH 7,0. Além disso, esse tratamento também reduz a atividade respiratória, atividade de enzimas oxidativas (POD e PPO) e promove a manutenção de compostos bioativos importantes para a hortaliça (Betalaínas, compostos fenólicos e flavonois) por 12 dias após o processamento. Na segunda etapa, quatro aditivos (arginina, cisteína, ácido cítrico e ácido ascórbico) e água destilada, como tratamento controle, foram comparados quanto à eficácia na conservação de beterrabas minimamente processadas. O tratamento com arginina promove os melhores resultados quanto a manutenção do aspecto visual e de compostos bioativos em relação aos demais aditivos. O modo de ação diferenciado da arginina favorece a redução do estresse oxidativo, estendendo a vida útil do produto. / White blush is the main postharvest issue in minimally processed red beet. This issue consists in dehydration of superficial cell layers of the product, resulting in a whitening aspect caused by the blockage of turgid and intact cells on the layers below. During the minimal processing preparation, cutting and manipulation of minimally processed products (MPPs) are considered source of abiotic stress, which induce the formation of reactive oxygen species (ROS). The accumulation of ROS causes biochemical and structural changes that directly affects the commercial quality. Food additives are used to slow the degradation of MPPs by keeping them fresh and suitable for consumption. Organic acids and amino acids are GRAS (Generally reconized as safe) additives widely used in vegetables. This study aimed to evaluate the efficacy of arginine in controlling white blush in minimally processed redbeet and compare with additives used commercially. Thus, initially it was determined the best combination of four doses of arginine (0, 10, 25 and 50 mM) with three pH ranges (unchanged, pH 6,0 and pH 7,0). Arginine treatment presents promising results regarding the white blush delay in minimally processed redbeet. In addition, this additive also reduces the respiratory activity, activity of oxidative enzymes (POD and PPO) and maintains the important bioactive compounds (betalains, phenolic compounds and flavonols) for 12 days after processing. In the second step, four additives (arginine, cysteine, citric acid and ascorbic acid) and distilled water, as control treatment, were compared for efficacy in conservation of minimally processed beets. Arginine treatment promotes the best results regarding the maintenance of the visual aspect and bioactive compounds content in relation to the other additives. The different mode of action of arginine favors the reduction of oxidative stress, extending the shelf life of the product.

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